Various methods for using a battery pack continuously are proposed.
Patent Document 1 (Japanese Unexamined Patent Publication No. 2003-217679) discloses the following discharge method. Whenever a battery voltage drops to a discharge termination voltage during discharge of a secondary battery, the secondary battery is intermittently discharged while repeating a temporary stop. In this case, when the discharge is restarted after a temporary stop, the discharge is performed while a discharge current is reduced in a stepwise manner. Thereby, compared to a case where high-rate discharge is performed continuously, it is possible to extract a great deal of power from a secondary battery.
In addition, Patent Document 2 (Japanese Unexamined Patent Publication No. H5-87896) discloses a battery residual capacity detection and correction method as described below. A battery residual capacity calculation value calculated from current consumption is corrected on the basis of a real battery residual capacity which is obtained in advance. Thereby, it is possible to perform a display or the like by further reducing a difference between a battery residual capacity and a battery residual capacity calculation value and obtaining an accurate battery residual capacity calculation value.